Radio antenna



Patented Apr. 14, 1953 UNITED STATES PATENT OFFICE 2,635,186 RADIO ANTENhlA reagents, Chicago, Ill. H Application October 7, 1943, Serial No; 53,365 1" ass-i; (01. 2504 This invention relates to radio antennas and is specifically directed toward the provision of an improved automobile antenna for broadcast band reception. l l

In introduction to this disclosure it, may be pointed out that, to be acceptable to the public and satisfactory in use, an automotiveantenna should include several desirable qualities; .that is, it should not only be sensitive, but also rugged, smooth operating and of presentable appearance. It has long been known, however, that these quale ities, while desirable in themselves, are nevertheless confiicting to a marked'extent, withthe result that all antennas previouslydeveloped have achieved one or more of the desirable qualities listed above only at the sacrifice of some other.

It will be remembered that the types of automotive antennas in common use maybe, generally divided into three groups; that is, the rooftop antennas, under-carriage antennas and the buggy Whip types. It is believed well known that certain developments of rooftop antennas have been,

found fairly satisfactory from an; electronic standpoint, but they have nevertheless failed to gain public acceptance; primarily for the reason that they are so inharmonious withthe styling.

of a modern motor car that the ordinary buyer will refuse to use this type of antenna irrespective of its efficiency. Conversely, the undercarriage types are also rapidly diminishing in popularity, sincealthough these do not detract from:

the appearance of the machine, yet they seldom perform successfully enough to be acceptable. No

doubt, the whip types are at present the most" popular, but these also have certain well defined shortcomings, primarily due to the fact that if they are used in retracted position the steel of the car roof partially shields them and results in more or less erratic performance, while if they are extended substantially above the car top they display an irritating tendency to swing back and forth in the drivers field of vision as a result of the movement of the car and the effects of wind. In addition, this type of antenna is necessarily so slender as to be quite delicate,

fragile and easily damaged, sometimes by e x is an attractive adjunct to the vehicle on which it is mounted.

,A, further object of the ,inventionis to accomplish this result without bringing about other disadvantageous features.v Specifically, itis an object of the invention to, accomplish the result by an antenna so constructed and designed that it haslittle, if, any, tendency to produce wind noises,

since itlhas been learned that, any efforts to increase the ruggednessiand strength of the conventional' whip antenna ordinarily, increase its size enough tov cause air turbulence behind the whip at high vehicle speeds. This produces suf ficient noise to causeavery perceptible increase in .the noise level with.n the vehicle; particularly the distressing, high frequency component of noise, which studies have indicated to be most irritating to the nervous system and to be a significant cause of irritation and fatigue.

, The, teachingsof this invention accomplish the foregoing objects, unite the several individually desirable qualities,,and reconcile, the prior confiicts by the provision of an antenna comprising,

: incombination a lower section in the form of a bulence and consequently without producing perceptible wind noise. This spar. serves as a mount for the slenderextension rod and holds it well above the car top, so, that it is not in any sense shielded by the metal of the car body.

The preferred embodiment of the invention-is illustrated in the drawings of this disclosure wherein; 1

Figure l is a fra gmental front pgspea v j ew' f, on, aut m bile ,ooo ,oow m e viooo io showing the preferred rnannerof installing an antenna constructed in accordance with these ch V,

, Figure Z is a vertical sectional View through the e antenna;

Figure 3 is, a "sectional view taken; stantially on the plane of the line 3--3 'of Fig 12;

Figure 4 is a detail an omobi e. side, pa e showin a m fi ma ner of mounting the antenna; and

Figure 5 is a detail cross sectional view of the antenna spar taken substantially on the plane of the line 5-5 of Figure 3.

The antenna spar generally indicated at E9 is streamlined in cross section, having a blunt leading edge I! with identical and opposite convex sides l2 of identical and compound curvature. These sides have their greatest curvature at the front, but extend rearwardly and gradually toward each other to meet at the point l3, so that the spar will move through the air without turbulence and without the production of eddy currents in its wake. The lower end of the spar is secured in any convenient manner to a mounting fitting 14 which is in turn preferably bolted to the upper fiat surface [5 of the vehicle but is insulated therefrom by an insulating sheet H and insulating washers l8. One of the mounting bolts l6 may be provided with a terminal lug l9 from which a lead-in wire 29 extends to the radio receiver.

The upper end of the spar NJ is closed by closure plug 2| in which a slide tube 22 is fitted. The plug may be secured to the spar in any convenient manner and the slide tube 22 may be most conveniently attached by pressing it into the bore 23 of the closure plug prior to assembly. The slide tube 22 carries a slender extension rod 24 which is fitted in frictional engagement within the tube so that the friction between the tube and the rod will hold it retracted or extended as desired. The rod 24 is preferably provided with an enlarged head 25 to facilitate manual raising and lowering of the rod and, in the preferred construction shown, the lower end of the rod is upset to form a stop 26 to prevent the rod from being entirely removed from the tube and spar.

A modified form of the invention shown in Figure 4 is of identical construction with the single exception that the base casting M is replaced by an angle fitting 28, in order that the antenna can be conveniently mounted on a vertical surface such as the side wall 27 of the vehicle fender or body.

The manner in which the structure shown accomplishes the objects of this invention will be recognized when it is pointed out that the spar II], which is of relatively heavy, rigid construction, extends substantially to the rooftop level of the car so that there is little likelihood of children playing about the machine damaging the antenna by bending. In addition, it is to be noted that the slide tube 22 in which the extension rod 24 is mounted is not only enclosed within the tubular spar but is spaced away from its walls, with the result that it is quite impossible to bend the tube and extension rod together in such a manner that the rod is interlocked within the tube, as is often done with conventional whip antennas. The extension rod 24 may be extended well above the roof level of the car, however, so that the metal of the roof does not exert a significant shielding effect on the antenna, nor detract from its electronic efiiciency.

The combination of the relatively large, heavy and rigid spar in the lower section of the antenna and the slender rod at the top also overcomes the irritating swinging and waving motion of conventional whip antennas, since the extension 24 need not be so long that it displays any marked tendency to swing, and also since its mounting is so far above the normal field of vision of the driver that any slight whipping that may take place is not at all objectionable.

The unusually large receptive surface area ex- 4 posed by the antenna provides for highly eflicien reception and gives good broad banding characteristics, yet at the same time it is so designed that this large surface does not impart turbulence or eddy currents to the air at high speed and thus is not objectionable from the standpoint of wind noise. The heavy, rigid, streamlined spar is attractive in appearance in itself, and is also styled in such a manner that it is harmonius with the present trends in automobile designing, with the result that the structure is not objectionable from an esthetic standpoint. It is, on the other hand, readily received in the trade and is regarded as an ornament rather than an eyesore.

From the foregoing it will be believed clearly evident that the teachings of this invention, by departing from prior practice, have brought forward a solution to a problem that has long perplexed an active industry. In short, they result in an improved antenna in which conflicting factors heretofore regarded as being irreconcilable have been brought together in such a manner as to retain the qualities of efficiency and ruggedness, yet at the same time to incorporate these qualities into a structure having suflicient inherent beauty of design and attractiveness as to be readily acceptable in a field where the physical appearance of the article is of sufi'icient importance to exclude any device that does not present a reasonably artistic appearance. It is accordingly submitted that the present invention marks an important advance in the art, and while it is no doubt subject to certain modifications and variations beyond the precise form here illustrated, its teachings can properly be considered to extend to any variation coming Within the terms of the appended claim.

Having thus described the invention what I claim as new and desire to protect by United States Letters Patent is:

An automotive antenna comprising, in combination, a generally vertical upright member consisting of conductive material throughout and in the form of a hollow, uniformly tapered metal airfoil spar of streamline cross section and larger at its lower end than at its upper end; an insulating base fitting comprising the sole support of said spar and secured to said spar at the lower end, a conductive closure fitting secured to and electrically connected with said spar at its up per end, a conductive guide tube mounted in said closure fitting and in electrical contact therewith and extending downwardly therefrom into the spar, and a metal extension rod of electrically conductive material extending through and in frictional sliding engagement with the guide tube, with means to limit the upward movement of the rod with respect to the tube, and a lead-in connection extending to the spar and thence through the closure fitting and guide tube to the extension rod.

THUR SCHMIDT.

References Cited in the file of this patent Carington et a1. Dec. 20, 

